Drill bit sharpener



y 968 H. D. COPELAND 3,382,738

DR ILL BIT SHARPENER Filed Feb. 16, 1966 2 sheets sheet 1 INVENTOR:

19%?040 2. la a/W0 H. D. COPELAND DRILL BIT SHARPENER May 14, 1968 2 Sheets-Sheet 3 INVENTOR I 15%?0402 (Zflizmw BY fl 7ATTORNEY Filed Feb. 16, 1966 United States Patent 3,382,738 DRILL BIT SHARPENER Harold D. Copeland, Commerce St, Loretta, Tenn. 38469 Filed Feb. 16, 1966, Ser. No. 527,667 9 Claims. (Cl. 7689.2)

This invention relates to a drill bit sharpener, and more particularly to a device for sharpening a drill bit with an explosively driven die.

Drill bits of the type used in drilling water wells, oil wells or blast holes in rocks can range in size from two to three feet long and weighing approximately twentyfive pounds to nine or ten feet long, and weighing two or three thousand pounds, depending upon the size of the drill hole, which can range from two inches up to two feet in diameter. These drill bits are made of strong and hard materials in order not only to withstand the wear and stress of the drilling to which they are adapted, but also to maintain the sharpness of their cutting edges as long as possible. Nevertheless, regardless of the size, strength and hardness of the bits, continual use and wear require such bits to be sharpened and re-sharpened.

It will be apparent from the size, weight and hardness of the material employed in such drill bits, that their sharpening requires substantial amounts of time, labor and expense.

The conventional method of sharpening such drill bits is by the manual labor of a blacksmith. A typical example of the expense of sharpening such a drill bit can be seen from the following example. A 250 pound, 6-inch bit on the average will be sharpened eighty times during its life. An ordinary bit of this size takes a blacksmith and helper about one and one-half hours to sharpen. If the estimated If the estimated blacksmiths wages are $2.75 an hour and the helpers wages are $2.30 an hour, the total labor cost for each sharpening would be about $7.60, or a total of $608.00 over the useful life of the bit.

It is therefore an object of this invention to provide a device for sharpening a drill bit with a minimum of time and expense.

Another object of this invention is to provide a device for sharpening a drill bit incorporating inexpensive materials and construction.

Another object of this invention is to provide a device for sharpening a drill bit incorporating a die projected at great speed to re-shape or forge the cutting end of the drill bit.

A further object of this invention is to provide a device for sharpening a drill bit incorporating a die projectile which is explosively driven against the cutting end of the drill bit.

Another object of this invention is to provide a device for rapidly re-shaping the cutting end of a drill bit which requires no special skill for operation.

Further objects and advantages of this invention will be apparent from the following description taken in conjunction with the drawings, wherein:

FIG. 1 is a perspective view of the invention disclosing a drill bit in phantom in operative position;

FIG. 2 is a sectional elevation taken along the longitudinal center line of the invention disclosed in FIG. 1, also showing the drill bit in phantom in operative position;

FIG. 3 is an enlarged section taken along the line 33 of FIG. 2;

FIG. 4 is an enlarged section taken along the line 4 of FIG. 2; and

FIG. 5 is a fragmentary section taken along the line 5-5 of FIG. 3.

Referring now to the drawings in more detail, a typical drill bit is disclosed in phantom in both FIGS. 1

3,382,738 Patented May 14, 1968 ice and 2. The bit 10 is provided with a cutting end 11, a body section 12, a wrench square 13, and a threaded end 14 adapted to be secured to a drilling rig, not shown.

The device 15 for sharpening the drill bit 10 includes an elongated base 16 comprising a pair of elongated spaced paralleled beams 17 and 18 rigidly fixed together by transverse spacer struts or plates 20.

Supported upon the rear portion of the base 16 by and between the beams. 17 and 18 is an explosion chamber or barrel 22, disclosed in a cylindrical shape with a thick wall of steel or other comparable material for resisting the explosion of gases within the chamber 22.

As disclosed in the drawings, the circular open front end 23 of the explosion chamber 22 is closed by a collar 24 comprising a lower half or section 25 and a separable upper half or section 26. The outer periphery of the collar 24 is not only adapted to fit within the open front end 23 of the explosion chamber 22, but the upper and lower sections 26 and 25 are adapted to fit about the opposite sides of and clamp the body section 12 of the drill bit 10 to maintain the cutting end 11 in its operative or sharpening position within the front end of the explosion chamber 22, as best disclosed in FIGS. 1 and 2. Since most conventional drill bits, including the disclosed drill bit 10, have water channels extending on opposite sides along the body section 12, the insides of the upper and lower collar sections 26 and 25 are provided with complementary configurations to securely engage the cross section of the body section 12 of the drill bit. As disclosed in FIG. 3, the upper collar section 26 is secured to the lower collar section 25 by means of the pins 28.

Since the body section 12 of different drill bits 10 of the same type may vary slightly in cross-sectional dimensions because of the various degrees of wear and forging, the collar sections 25 and 26 are preferably separated by spacing 30 to permit contraction where the body section 12 is of smaller cross-section than usual. Moreover, the outer periphery 31 of the collar sections 25 and 26 taper rearward and inward as shown in FIG. 2 to adjust for the outer diameter of the collar 24 which will vary with the cross-section of the body sections 12. The pins 28 may also be provided with vertically elongated slots and wedges 32 therethrough for additionally securing the upper collar section 26 to the lower collar section 25.

The opposite end of the drill bit 10 from the cutting end 11 may be supported by a stanchion 33' having a groove 34 for supporting the wrench square 13 and posts 35 extending upwardly on opposite sides of the drill bit 10 extending through mating apertures in a yoke 36 fitting over the top of the wrench square 13. Posts 35 may be provided with elongated openings to receive the wedge pins 38 in order to maintain the yoke 36 and stanchion 33 firmly and securely about the wrench square 13.

The stanchion 33 is held or scotched against rearward movement by means of stop pins such as 40 inserted into mating holes 41 longitudinally spaced in the tops of the beams 17 and 18.

Movably received longitudinally within the explosion chamber 22 is the die 45 having a front face 46 and a rear face 47. Formed in the front face 46 is the desired complementary shape 48 of the cutting end 11 of the drill bit 10. The cross-section of the die 45 is identical in shape and size to the inner cross-section of the explosion chamber 22. For example, the explosion chamber 22 disclosed in the drawings is cylindrical, and consequently the die 45 is also cylindrical having an outer diameter substantially equal to the inner diameter of the chamber 22. The tolerance between the outer dimensions of the die 45 and the inner dimensions of the explosion chamber 22 are such as to permit free longitudinal movement of the die 45 through the chamber 22, without any material 3 leakage of explosion gases between the die 45 and the chamber 22.

Since the disclosed chamber 22 and die 45 are cylindrical, the rotational movement of the die 45 within the explosion chamber 22 must be constrained so that the complementary die shape 48 will accurately align with the corresponding parts of the cutting end 11. Therefore, straight elongated grooves 49 and 50 are formed as tracks or guideways in the inner surface of the explosion chamber 22 and extend throughout its length. Mating elongated straight tongues or ribs 51 and 52 project from the periphery of the cylindrical die 45 to be slidably received in the grooves 4-9 and 50, and to prevent relative rotation. Of course, if the chamber 22 and die 45 had other cross-sectional shapes, such as a square, then the grooves 49 and 5t and the tongues 51 and 52 would be unnecessary because the inherent shape of the square chamber 22 and square die 45 would automatically prevent relative rotation between the two parts.

The rear end 55 of the explosion chamber 22 is preferably open and large enough to permit the die 45 to be inserted in and removed from the chamber 22, and to permit interchangeability of dies 45 having different die shapes 48.

Adapted to close the open rear end 55 is a cover or door 57 which is pivoted about the hinge pin 53 to the rear portion of the explosion chamber 22, and which may be locked in closed position by means, such as the pivoted latches 59, which are likewise hinged to the rear portion of the explosion chamber 22 by means of the hinge pins 60.

An explosive charge, such as a cartridge 62 may be inserted through the open rear end 55 and located immediately behind the rear face 47 of the die 45 and retained within the explosion chamber 22 by means of the latched cover 57. A firing pin 63 is mounted in the center of the cover 57, biased to a retracted inoperative position by means of the spring 64, and in alignment with the cap on the cartridge 62. With the die 45 and cartridge 62 located in their initial operative positions as disclosed in FIG. 2 and the cover 57 closed and latched, the firing pin 63 may be struck manually with a hammer to detonate the cap, explode the cartridge 62, causing the immediately exploded gases to drive the die 45 forward in the direction of the arrow in FIG. 2, with tremendous speed and force against the cutting end 11 of the drill bit 12. If the cutting end 11 has been properly heated before it is clamped in the explosion chamber 22 by means of collar 24, then the forceful impact of the die 45 against the cutting and 11 will forge a new, well-defined cutting face and edges upon the cutting end 11 of the drill bit 12.

.In order to make the forging operation more efiicient, a plurality of openings 66 are formed entirely through the upper and lower collar sections 26 and to rapidly exhaust any air or gases trapped within the explosion chamber 22 between the rear die face 46 and the collar 24, so that these gases will not be compressed to break the forward acceleration of the die 45.

In addition to the front exhaust openings 66, one or more side ports 67 are formed to extend radially through the wall of the compression chamber 22 in the forward portion of the compression chamber. Moreover, the ports 67 are preferably located, for their optimum effect, slightly behind the rear face 47 of the die 45 after the die has attained its extreme forward forging or operative position. When the side ports 57 are so located, they permit immediate exhaustion of the explosive gases from the chamber 22 after the die 45 has completed its work upon the cutting end 11.

The simplicity of the operation of the invention is readily apparent from its construction. The cutting end 11 of the drill bit 10 is heated to redness, and the drill bit is then clamped Within the collar 24. and between the stanchion 33 and yoke 36, as disclosed in FIGS. 1 and 2. The collar 24 is then inserted into the open front end 23 of the explosion chamber 22 until the periphery 31; is wedged tightly. A stop pin is inserted into a registering pin hole 41 in each beam 17 and 18 immediately behind the stanchion 33, as disclosed in FIG. 2, so that the cutting end 11 is firmly and accurately located within the explosion chamber 22 adjacent the front end 23. A die 45 having the identical complementary shape 4% for the cutting end 11. is then inserted through the open rear end of the chamber 22 until the die 45 is slightly forward of the rear end 55 as disclosed in PEG. 2. The cartridge 62 or other explosive charge is then introduced into the open rear end 55 into the chamber 22 behind the die 45. The cover 57 is swung about its hinge pin 58 to a closed position and latched firmly in place and sealed against the Open rear end 55 by means of the pivoted latches 59.

Then, with a small hammer, the operator strikes the firing pin 63 to detonate the cartridge 62 creating the explosion which impels die 45 rapidly along the barrel or chamber 22, expelling the gases from the chamber 22 in front of the die 45 through the front exhaust openings 66, and also through the side pontholcs 6'7. The rapid acceleration caused by the explosion provides suficient force for the die shape 48 toform a new and well-defined cut-ting shape upon the hot cutting end 11 of the drill bit 12. As soon as the die 45 strikes the cutting end 11, the explosive gases behind the die 45 will exhaust through side ports 67 to rapidly relieve the explosive force behind the die 45. Stop pins 41 and wedge pins 38 may then be removed so that the yoke 36 can be raised and the drill bit 12 and collar 24 pulled forwardly from the compression chamber 22. After the collar 24 is removed from the body section 12, and the cutting end 11 cooled, the drill bit 10 is ready for operation.

The die 45 may be removed after the door is unlatche-d and opened. Then the die 45 may be stored for future operations or replaced by other dies having shapes 48 corresponding to the drill bit 10 to be sharpened.

It is apparent that such a drill bit sharpening device 15 will easily, rapidly and efiiciently form the desired shaped face upon the cutting end 11 of a drill bit 10 without requiring skilled labor such as a blacksmith. Such a drill bit sharpening device 15 fills a long felt need in the ant of sharpening drill bits of the type used in heavy drilling where expense and time have long been a deterrent.

It will therefore be apparent to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof, and therefore, the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

-1. A device for sharpening a drill bit comprising:

(a) an elongated explosion chamber of uniform crosssection, having a front end and a rear end,

(b) means for holding the cutting end of said drill bit exposed within the front end of said chamber,

(c) a die having a face shaped with the complementary configuration of the cutting end of said drill bit, and having the same cross-sectional shape as said chamber,

(d) said die being mounted with said face forward in said chamber for free longitudinal movement therein, but constrained against rotational movement,

(c) means in the rear end of said chamber for detonating an explosive charge behind said die to drive said die forward, and

(f) means in the forward portion of said chamber for exhausting gases from said chamber as said die moves toward said bit.

2. The invention according to claim 1 in which said means for exhausting said gases comprises at least one porthole formed through the wall of said chamber slightly to the rear of the posit-ion of said die in which said die strikes the cutting end of said drill bit.

3. The invention according to claim 1 in which said means for exhausting gases comprises at least one open-: ing through the forward end of said chamber in front of said die.

4. The invention according to claim 3 further comprising at least one porthole through the wall of said chamber slightly behind .the position of said die in which said die strikes the cutting end of said drill bit.

5. The invention according to claim 1 in which said rear end comprises an opening through which said die is adapted to pass and a door for closing said opening.

6. The invention according .to claim 5 further comprising an explosive charge in said explosion chamber between said die and said door, said detonating means being mounted in said door for exploding said charge when said door is closed.

7. The invention according to claim 1 in which said front end comprises a collar adapted to be received in said front opening and to hold said drill bit in alignment with said die, said collar having gas discharge openings to permit the exhaustion of gases in advance of said moving die.

8. The invention according to claim 7 in which said collar comprises a pair of opposed sections adapted to fit on opposite sides of said drill bit, the outer periphery of said collar section being tapered inwardly and rearw-ar-dly to provide means for adjust'ably fitting said collar within said front opening to compensate for minor variations in the cross-sectional side of said drill bit.

9. The invention according to claim 1 in which said explosion chamber is cylindrical and said die is cylindrical and of substantially the same diameter as said chamber, an elongated straight groove in the inner wall of said explosion chamber, and a mating elongated tongue on the outer periphery of said die for slidably engaging said groove.

References Cited UNITED STATES PATENTS 2,648,125 8/ 195 3 McKenna et a1. 294221 2,395,354 2/ 1946 Temple 2227-9 3,293,732 12/1966 Broske 2942l 3,3-27,5 6-8 6/ 1967 Meyer 76-892 RICHARD J. HERBST, Primary Examiner. 

1. A DEVICE FOR SHARPENING A DRILL BIT COMPRISING: (A) AN ELONGATED EXPLOSION CHAMBER OF UNIFORM CROSSSECTION, HAVING A FRONT END AND A REAR END, (B) MEANS FOR HOLDING THE CUTTING END OF SAID DRILL BIT EXPOSED WITHIN THE FRONT END OF SAID CHAMBER, (C) A DIE HAVING A FACE SHAPED WITH THE COMPLEMENTARY CONFIGURATION OF THE CUTTING END OF SAID DRILL BIT, AND HAVING THE SAME CROSS-SECTIONAL SHAPE AS SAID CHAMBER, (D) SAID DIE BEING MOUNTED WITH SAID FACE FORWARD IN SAID CHAMBER FOR FREE LONGITUDINAL MOVEMENT THEREIN, BUT CONSTRAINED AGAINST ROTATIONAL MOVEMENT, (E) MEANS IN THE REAR END OF SAID CHAMBER FOR DETONATING AN EXPLOSIVE CHARGE BEHIND SAID DIE TO DRIVE SAID DIE FORWARD, AND (F) MEANS IN THE FORWARD PORTION OF SAID CHAMBER FOR EXHAUSTING GASES FROM SAID CHAMBER AS SAID DIE MOVES TOWARD SAID BIT. 